Disruption of the inner-segment/outer segment (IS/OS) junctionon Spectral Domain Optical Coherence Tomography (SDOCT) imagesis used clinically as an indicator of loss or damage to macularphotoreceptors. We sought to validate this interpretation bycomparing cones visualized with AOSLO with registered en faceSDOCT photoreceptor slab images.

Methods:

Patients with MacTel, AMD, and Best’s vitelliform dystrophywere imaged at multiple time points using SDOCT and AOSLO. AOSLOimages were processed and registered to clinical images. Individualhigh quality AOSLO frames were selected such that well-resolvedcone mosaics and regions of non-resolved cones were selectedand individual cones were labeled. The individual cone photoreceptorsand No Cone Regions (NCRs) were then labeled in these frames.En face IS/OS reflectivity slab images were created using anautomated RPE segmentation (CZMI) and were registered to clinicalimages independently.

Results:

Regions where there is significantly decreased pixel intensityin the IS/OS slab images fit entirely within the NCRs seen withAOSLO. However, cone mosaics are sometimes not visible in AOSLOimages where there appears to be an intact IS/OS junction onSDOCT. Regions of disagreement between AOSLO and SDOCT are discreteand in some situations follow the same border pattern (image).Data processed quantitatively by the use of a receiver operatingcharacteristic (ROC) metric between the NCR and the SDOCT IS/OSdata demonstrates the sensitivity and specificity between themodalities when defining high quality AOSLO locations as thegold standard.

Conclusions:

The strongest correlations exist between AOSLO NCRs and absentIS/OS slab intensity. One possible explanation for this is thatstructurally intact photoreceptors which can be visualized bySDOCT IS/OS slabs may not waveguide properly and thus not bevisible on AOSLO.